Note 81 — OBSERVATIONS ON THE MINERALOGY AND GEOLOGY OF A PART OF THE UNITED STATES WEST OF THE MISSISSIPPI.

What explanation the advocates for the doctrine of the recent emersion of our continent will give of the highly and exclusively primitive character of the Rocky Mountains, we are at a loss to conjecture. The organized remains hitherto observed in the secondary aggregates along the base of those mountains, are mostly of animals supposed to have inhabited the depths of the ocean. But if the granite of the Rocky Mountains has been forced up at a recent period, where are the traces of all those older secondary, and fletz rocks, which should have intervened between it and the horizontal sandstones? If these mountains had formed the shores of that ocean, in which the greater part of our continent was so long immersed, after the elevation of the old world, we should have expected to find along their base, the remains of littoral animals, and not of those which inhabited the depths of the ocean. It would be proper, however, before we refer to the character of the Rocky Mountains, as invalidating or confirming any system of opinions, to ascertain that their eastern and western sides are in all respects similar.—James.